I suggest you ...

Reopen and maintain a public bug tracker and tie it into regression testing.

The xen.org bugtracker fell out of grace almost a dozen years now.
It would be good to have one and integrate it in the Xen release management.

Otherwise many more people aren't just affected by bugs or other issues, but they also all need to spend time discovering / debugging and researching it.
Using a "lively" bug tracker would also allow to verify if a problem is fixed.

If we can find a group of volunteers to tend and manage the bugtracker, we might consider opening one again. If you want to see this happen, find some like-minded people and make a proposal on the mailing list.

The problem is that we don't have people to go through and maintain the bugtracker. If we could get a group of volunteers to go through the bug tracker, look for duplicates, and report genuine problems to the mailing list, then that might be able to be made to work. Absent such a community-driven effort, bringing it back is only asking for more trouble.